What makes the new Honda V8 outboard so special?

A new 350hp Honda V8 outboard puts Honda back in the big league. We take a look at its most powerful outboard yet

After years of watching from the sidelines as Mercury, Yamaha and Suzuki fought for supremacy in the battle of the big outboard engines, Honda has finally joined the fray. The new Honda V8 outboard, BF350 is a state-of-the-art 350hp V8 engine boasting a raft of features designed to give it a technological edge over its competitors.

The starting point is a new 5-litre V8 block built solely for marine use. With the exception of a handful of racing car engines, this is the first V8 Honda has developed for sale and its most powerful outboard yet – its previous flagship only mustered 250hp.

Developing a true 350hp at 5500rpm measured at the propeller shaft (some manufacturers quote max power at the engine output, ignoring frictional losses incurred in the gearbox), it is designed for use on planing craft over 25ft. Honda is also keen to point out that it will do this while operating on regular 86 octane E10 unleaded fuel rather than premium high octane E5 unleaded.

Trim support automatically adjusts the engines’ trim angle to suit the boat’s speed

Honda V8 power

However, it’s the way it delivers that power as much as the number itself that is said to impress, in particular its “smooth response” and “exceptionally robust torque.” Much of that comes down to the engine’s high-tech breathing apparatus, including Honda’s VTEC (Variable Valve Timing & Lift Electronic Control) technology.

This uses a single camshaft per cylinder bank to operate its 32 valves but with two distinct cam profiles. At low RPM a mild cam profile operates the intake valves for a broader, flatter torque curve and a smooth power delivery, while at high revs a more aggressive cam profile kicks in for freer breathing to help squeeze every last drop of power from each cylinder.

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Assisting this is another of Honda’s trademarked technologies, known as BLAST (Boosted Low Speed Torque). Essentially, this is a clever bit of software programming that advances ignition timing and injector flow to create a more potent air/fuel mixture that boosts torque for more rapid acceleration.

Once up and running, lean burn control technology automatically adjusts this air-fuel mixture to match the speed and load in cruise mode (between 2,000 and 4,500rpm) so that it burns as little fuel as possible to maintain that speed.

The use of low-friction ion plating on the piston rings and “advanced plateau honing” of the cylinder bores also helps to increase fuel efficiency while at the same time reducing wear and engine noise.

Narrow angle V8 allows for a slim profile. Silver and white cowlings are available

However, it’s not just the engine technology that Honda has lavished attention on, the operating systems have also received a major upgrade as well. The most interesting of these is a new automatic trim system called Trim Support that adjusts the outboard leg’s trim setting according to the engine or boat speed.

Rather than being infinitely adjustable, this has three factory presets that can be customised by the user to suit their own boat and preferences, a little like a set of automatic trim tabs. This can easily be over-ridden by pressing the trim button up or down as usual.

Variable valve timing combines strong low-rev torque with top-end power

Auto trim and tilt

Less sophisticated but just as useful for many is the new Automatic Tilt mechanism – once the engine is switched off, two presses of the tilt switch will cause the engine to lift or lower the whole way up or down rather than having to keep your thumb on the button for the duration.

Lastly, a cruise control button allows boaters to maintain a given speed or RPM setting even when towing a wakeboarder, making tight turns or simply low-speed trolling while fishing.

Charging capacity has become another key battleground for big outboard engines due to the proliferation of power hungry electronics on big day boats such as air-conditioning, cooking facilities and gyro stabilisers. The BF350 kicks out a healthy 70A maximum and is NMEA 2000 certified so that all the engine data can be interfaced with navigation equipment from all the major suppliers. Multiple engine installations can also be linked to an Optimus 360 joystick controller for simpler one-handed berthing manoeuvres.

Naturally aspirated 5.0-litre V8 should ensure a very refined power delivery

Sleek looks

Last but by no means least is the engine’s sleek appearance. The block itself features a narrow angle 60° vee housed inside a slimline casing. Available in Honda’s traditional Aquamarine silver or Grand Prix white colours, with a black stern cover and chrome trim, it looks far more modern than its existing range of outboards.

Unfortunately, these slender looks flatter to deceive as the new BF350 tips the scales at 347kg (355kg including propeller), making it appreciably heavier than its two main 350hp rivals from Mercury and Suzuki (Yamaha doesn’t currently have a 350hp engine in its range).

Prices for the new BF350 start at £29,500 inc VAT and Honda says it will be backed by what it claims is an industry-leading “true five-year non-declining factory warranty.” This means it covers exactly the same things on the last day as it does on the first.
Whether this all adds up to a stronger package than its 350hp rivals remains to be seen, but in the meantime it’s good to have the originators of the four-stroke outboard engine back in the big league once again.

Honda V8 outboard specifications

Max power: 350hp
Max revs: 6000rpm
Displacement: 5-litre
Cylinders: V8
Weight: 355kg
Price: from £29,500 inc VAT
Contact: www.honda.co.uk

This article What makes the new Honda V8 outboard so special? appeared first on Motor Boat & Yachting.

Source: https://www.mby.com/gear/what-makes-the-new-honda-v8-outboard-so-special-129742